The Lactational Amenorrhea Method of contraception (LAM) was formalised over 20 years ago[i] and the Faculty of Sexual & Reproductive Healthcare (FSRH) guidance on postnatal sexual and reproductive health [ii] is clear:

“Women may be advised that if they are<6 months postpartum, amenorrhoeic and fully breastfeeding, the lactational amenorrhoea method (LAM) is over 98% effective in preventing pregnancy.

Women using LAM should be advised that the risk of pregnancy is increased if the frequency of breastfeeding decreases (stopping night feeds, supplementary feeding, use of pacifiers), when menstruation returns or when >6 months postpartum”

Yet a recent survey[iii] found “particular inconsistencies” in the advice given to breastfeeding women in the UK